Conductor support for transition from gas bus enclosure tube to power circuit breaker

ABSTRACT

An insulation disk or cone supports the conductor extending from a power circuit breaker to a gas-filled bus, and also serves as a gas barrier.

United States Patent 91 Gdaglione 1 Jan. 22, 1974 CONDUCTOR SUPPORT FOR TRANSITION FROM GAS BUS ENCLOSURE TUBE TO POWER CIRCUIT BREAKER Inventor: Giovanni Paolo Guaglione, Irvine,

Calif.

Assignee: I-T-E Imperial Coroporation,

Philadelphia, Pa.

Filed: Oct. 27, 1972 App]. No.: 301,643

US. Cl. 174/18, 200/148 R Int. Cl. H0lh 33/02, HOlb 17/26 Field of Search... 174/18, 23 R, 31 R, DIG. 10;

References Cited UNITED STATES PATENTS Easley et al 174/23 R X Frowein 174/23 R X McKeough 200/148 R Roth 317/103 X Graybill 174/18 Primary Examiner-Laramie E. Askin Attorney, Agent, or FirmSidney G. Faber et al.

ABSTRACT An insulation disk or cone supports the conductor extending from a .power circuit breaker to a gas-filled bus, and also serves as a gas barrier.

8 Claims, 3 Drawing Figures PAIENI JAN Q 157-1 3,787. 5 4

" sum 1 [1F 3 Pmmium-z SHEET a m a 3.787. 604

CONDUCTOR SUPPORT FOR TRANSITION FROM GAS BUS ENCLOSURE TUBE TO POWER CIRCUIT BREAKER RELATED APPLICATIONS This application is rela'ted to application Ser. No. 301,642, filed Oct. 27, 1972, entitled CIRCUIT BREAKER CONNECTION TO GAS INSULATED BUS, in the names of Graybill and Wilson, assigned to the assignee of this invention.

BACKGROUND OF THE INVENTION BRIEF SUMMARY OF THE INVENTION In accordance with the invention, an insulation disk or equivalent cone is provided to support the outgoing circuit breaker relative to the circuit breaker housing and to form a seal across the circuit breaker tank opening through which the conductor passes. The present invention, therefore, eliminates the need for an entrance bushing at the transition between bus and breaker. Moreover, a disconnect switch can be mounted vertically'above the breaker and have minimum construction height.

The novel transition of the invention has a minimum cost and generally will have a larger diameter than the diameter of the bus since its diameter can be determined by that of the disconnect switch. These insulators will also provide improved field distribution near theterminal end of the conductor and inside the circuit breaker. I

While the novel transition can be used for one or both breaker terminals for a given phase, its low height allows mounting of a vertical disconnect switch on one terminal, while still sufficient clearance to an outdoor bushing on the other terminal.

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF THE DRAWINGS Referring first to FIG. I, there is shown a power circuit breaker, such as a 230 KV breaker which may be of the type shown in U. SfPat. No. 3,526,734. Thus, there is provided a grounded housing 10 which is filled with SF, at relatively low pressure, for example, 3 atmospheres. Two high pressure reservoirs II and 12 are mounted on insulators l3 and 14 respectively within tank 10, and are supplied with high pressure SF from high pressure reservoir 15. Each of high pressure tanks 11 and 12 supports pairs of interrupters I6-I7 and 18-19 respectively which may each have appropriate impedances 20 to 23 respectively across their contacts. Each of interrupters 16 to 19 is connected in series with one another to define four series breaks for the circuit breaker. While these interrupters are operating, high pressure gas from reservoirs I1 and 12 is released through the contact gap and into the low pressure interior in the manner described in the above patent.

A conventional entrance bushing 30 is shown in FIG. 1. Thus, bushing 30 has a central bushing conductor connected to interrupter 16 and supported relative to tank 10 by a conical insulator portion 32. Conical insulator 32 is suitably fixed to the breaker bushing pocket 33. A current transformer 34 surrounds the breaker bushing pocket 33 as shown.

Conventionally, a second entrance bushing, similar to bushing 30, would pass through breaker bushing pocket 40 for connection to interrupter 19. In accordance with one aspect of this invention, and where the transition is to be made to a gas-filled bus, or gas-filled disconnect switch, or the like, an insulation disk is used to form a conductor support and gas seal. Note that the entrance bushing 30 of FIG. I could be replaced by this type structure if desired.

The novel transition structure consists of a conductive tube 50 having spaced disk insulators 51 and 52 suitably secured at its opposite ends. A conductor 53, extending from interrupter 19, passes through and is sealed relative to spaced insulators 51 and 52 and thereby is supported relative to pocket 40. More specifically, tube 50 is welded to bolt ring 53a which is, in turn, bolted with a gas-tight seal to the flange 54 of bushing pocket 40. Note that bushing pocket 40 supports and is surrounded by current transformer 55. Note that disk 51 serves as a primary gas seal as well as a conductor support. Moreover, the voltage distribution across disk 51 is favorable as compared to the distribution across conical insulator 32.

A major advantage of the novel transition is that it allows low construction height. Moreover, it allows the vertical mounting of a gas-filled disconnect switch, which is, in turn, connected to a gas bus run, without exceeding the height of the conventional entrance bushing 30. Thus, in FIG. 1, there is shown an SF filled disconnect switch 60 which is, in turn, connected to a gas-filled transmission line 61.

More specifically, disconnect switch 60 is formed of cooperable contacts 62-and 63 which are supported within generally cylindrical sections 64 and 65 respectively by disk insulators 66 and 67 respectively. A manhole 68 provides access to switch 60.

One end of switch '60 is connected by boltconnecting flanges 70 and 71 to the elongated gas-filled bus 61. The other end of switch 60 is connected to conductor 53 through triangular transition joint 73. Joint 73 is terminated at opposite ends by flanges 74 and 75 respectively. Flange 74 is bolted to flange 53a and flange 75 is connected to flange 76 of cylinder 64. Conductor 77, extending from contact 62, is connected to the upper end of conductor 53 by the T-shaped conductor 80 which may be suitably bolted to span the conductor ends. A handhole 81 is provided to allow this connection to be conveniently made.

In the above, an auxiliary support structure or foundation may be provided to support switch 60. FIGS. 2 and 3 show a novel connection structure at joint 73 of FIG. 1 which makes auxiliary support structures unnecessary, and which simplifies the connection and disconnection procedure at joint 73 for replacement of current transformers or breakers without depressurizing the disconnect switch 60 and while contact 63 is still energized. Moreover, the novel connection structure of FIGS. 2 and 3 could be applied to other breaker transition terminals'than that shown in FIG. 1 for conductor 53.

Referring to FIG. 2, there is shown a portion of tank of FIG. 1 and of pocket 40 of FIG. 1. FIG. 2 further shows the provision of a platform 80, secured to pocket 40, for supporting the schematically shown current transformer 81. Conductor 53 of FIG. 1 is also shown extending through pocket40. Conductor 53 in FIG. 2 terminates at face 83 and contains tapped openings (not shown) to receive connection bolts such as bolts 84 and 85, as will be later described.

FIG. 2 further shows a portion of the disconnect switch 60 of FIG. 1, including housing 64, switch jaw 62, disk insulator 66 and flange 76. Note that disk 66 forms a gas-tight seal with housing 64.

The disconnect switch 60 of FIG. 2 further has an extending cylindrical housing portion 90 having flange 91 connected to flange 76. Housing portion 90 further has a bottom flange 92 and a gas-fill port 93. A removable triangular section 94 is then provided wih flanges 95 and 96 which are connected in gas-tight relation'to flanges 92 and 97 respectively by bolts such as bolts 98-99 and 100-101 respectively. Flange 97 is formed on extension cylinder 102 of pocket 40. An' access port 103 is formed in section 94,to ggin access to sliding conductive tube 105.

Sliding tube 105 has abolt ring 106 on its bottom which is bolted to conductor 53 by bolts 84 and 85. The

upper end of tube 105 is slidably received by inwardly biased contact fingers 107 and 108 and can slide into the tubular conductor 109 welded to the disconnect switch jaw contact 62. Tube105 can reach the dottedline position 105a shown in FIG. 2.

' If it should ever become necessary tochange, add, or 'remove. one of the current transformers 81, the construction of FIG. 2 permits the following procedure:

1. Attach gas reclaimer hose to fill port 93 and pump SF gas out of the enclosure between gas barrier 66 and the breaker bushing or a further barrier, such as barrier 51 of FIG. 1.

2. Remove the access port cover 103.

3. Remove the bolts 84 and 85 attaching the small diameter, sliding conductor tube 105 to the top of the bushing.

' 4. Provide temporary scaffolding to support the disconnecting switch 60 in place.

5. Remove bolts 9899 and 100-101 from the top and bottom flanges of the removable section 94 of the grounded enclosure tube.

6. Reaching in through the access port 103, slide the small diameter conductor tube 105 up into the large diameter tube 109 above, and slide the removable enclosure section 94 toward the left, removing it completely.

7. Raise the current transformers 81, one at a time, and slide them horizontally through the gap in the conductor and enclosure tubes 90 and 102 provided in the steps (1) through (5) above.

and bolted in place on the bushing, the access port 103 replaced, and the section between the gas barrier 66 the work can be done with the upper switch contact (63 in FIG. 1) energized at normal voltage.

Another embodiment of the invention is shown in FIG. 3. In FIG. 3 components similar to those in FIG. 1 or 2 have similar numeralsv In this arrangement, the metal enclosure surrounding the upper portion of conductor 53 is also conneted to the breaker bushing pocket 40 with a flanged, bolted, gasketed and insulated joint. A telescoping tubular metal housing 121 is attached to enclosure 120 near the top by means of a fillet weld 122. The top of the telescoping housing 121 is attached to the bottom of the disconnecting switch housing 123 by means of a flanged, bolted and gasketed joint including flanges 76 and 91.

Internally, a conductor tube 126 is connected to and supported from the top of the conductor 53 by six bolts, such as bolts 1 24 and 125. A ggp between the conductor tube 126 and the disconnect switch conductor tube 109 is normally bridged with a multiplicity of flexible metal connectors 127, which are bolted to lower and upper terminals 128 and 129 attached, respectively, to the bushing and disconnect switch conductor tubes 126 and 109. The flexible connectors 127 are covered with an electrostatic shield 130 (nonnally attached with screws to the upper terminal, not shown) to avoid concentration of dielectric stress at sharp edges in this area.

As in FIG. 2, normally the weight of the disconnectand the breaker bushing or disk insulator.

2. Provide temporary scaffolding to support the disconnecting switch 60 in place.

3. Using an electric or pneumatic chisel, chip off the weld 122 at the bottom of the telescoping metal housing 121.

4. Remove the bolts and 141 from the flanged joint between flanges 76 and 91 at the top of the telescoping metal housing 121.

5. Drop the telescoping metal housing 121 as far as it will go.

6. Remove the screws at the top of the electrostatic shield 130, and drop the shield 130 as far as it will go.

7. Unbolt and remove the flexible connectors 127 and terminals.

Steps (1) through (7) immediately above provide a gap in both conductor and enclosure tubes, permitting removal and replacement of current transformers 55, and permitting the entire circuit breaker to be removed or replaced, if necessary.

It will be seen from FIGS. 2 and 3 that means are provided for supporting the disconnecting switch assemblies 60 from the circuit breaker tanks, requiring no additional space and no separate supporting structures for the switches. At the same time, simple means are provided for establishing an open gap in both the conductor and enclosure between the breaker and the disconnect switches, to permit replacing current transformers or moving the breaker while the disconnect switch and bus above are pressurized and energized at normal voltage. 1

Finally, means are provided for insulating the enclosure tube joint at the breaker bushing, to prevent induced currents in the enclosure from flowing through the current transformers and thus giving incorrect current indication. Thus, in H6. 2 an insulation gasket 140 prevents the flow of induced currents in the tank from circulating current in the enclosure tube.

Although there has been described a preferred embodiment'of this invention, many variations and modifications will now be apparent to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. in combination, an entrance bushing and a circuit breaker; said circuit breaker having an outer sealed enclosing housing; said circuit breaker having at least one internal terminal member for connection to conductors disposed externally of said outer sealed enclosing housing; said housing having an opening therethrough; said entrance bushing including an open-ended cylinder extending through said opening with the exterior of said cylinder sealed to and fixed to the periphery of said opening; a conductor member extending from said internal terminal member and extending through said cylinder and being disposed generally along the axis of said cylinder; an insulation support member formed generally circularly in cross-section and centrally receiving said conductor member; the external periphery of said insulation support member being fixed and sealed relative to the interior surface of said cylinder; and a second insulation member connected to and extending between said conductor member and the interior surface of said cylinder, said second insulation member being spaced from said insulation support member along the axis of said cylinder and the axis of said conductor member.

2. The combination of claim 1 wherein said outer sealed enclosing housing is of conducting material and is connected to ground potential.

3. The combination of claim 2 wherein said housing is filled with a gas which contains SF as at least one constituent thereof under positive pressure; said insulation support member serving as a gas seal across said opening.

4. The combination of claim 2 wherein said cylinder is of conductive material.

5. The combination of claim 4 whereinsaid insulation support member isan insulation disk having a thickness which decreases. from its center toward the outer periphery thereof.

6. The combination of claim 1 which further includes a plurality of entrance bushings for said circuit breaker each having an identical construction to the construction of said entrance bushing and including respective open-ended cylinders extending through respective openings in said housing and respective insulating support members for supporting respective conductor members extending through the said plurality of cylinders.

7. The combination of claim 1 wherein said cylinder has first and second ends; said insulation support member and said second insulation member being fixed adjacent said first and second ends respectively of said cylinder.

8. The combination of claim 7 which further includes a plurality of entrance bushings for said circuit breaker each having an identical construction to the construction of said entrance bushing and including respective open-ended cylinders extending through respective openings in said housing and respective insulating support members for supporting respective conductor members extending through the said plurality of cylin-' ders. 

1. In combination, an entrance bushing and a circuit breaker; said circuit breaker having an outer sealed enclosing housing; said circuit breaker having at least one internal terminal member for connection to conductors disposed externally of said outer sealed enclosing housing; said housing having an opening therethrough; said entrance bushing including an open-ended cylinder extending through said opening with the exterior of said cylinder sealed to and fixed to the periphery of said opening; a conductor member extending from said internal terminal member and extending through said cylinder and being disposed generally along the axis of said cylinder; an insulation support member formed generally circularly in cross-section and centrally receiving said conductor member; the external periphery of said insulation support member being fixed and sealed relative to the interior surface of said cylinder; and a second insulation member connected to and extending between said conductor member and the interior surface of said cylinder, said second insulation member being spaced from said insulation support member along the axis of said cylinder and the axis of said conductor member.
 2. The combination of claim 1 wherein said outer sealed enclosing housing is of conducting material and is connected to ground potential.
 3. The combination of claim 2 wherein said housing is filled with a gas which contains SF6 as at least one constituent thereof under positive pressure; said insulation support member serving as a gas seal across said opening.
 4. The combination of claim 2 wherein said cylinder is of conductive material.
 5. The combination of claim 4 wherein said insulation support member is an insulation disk having a thickness which decreases from its center toward the outer periphery thereof.
 6. The combination of claim 1 which further includes a plurality of entrance bushings for said circuit breaker each having an identical construction to the construction of said entrance bushing and including respective open-ended cylinders extending through respective openings in said housing and respective insulating support members for supporting respective conductor members extending through the said plurality of cylinders.
 7. The combination of claim 1 wherein said cylinder has first and second ends; said insulation support member and said second insulation member being fixed adjacent said first and second ends respectively of said cylinder.
 8. The combination of claim 7 which further includes a plurality of entrance bushings for said circuit breaker each having an identical construction to the construction of said entrance bushing and including respective open-ended cylinders extending through respective openings in said housing and respective insulating support members for supporting respective conductor members extending through the said plurality of cylinders. 